Peel or not peel the potatoes. Slice
them thin but not too thin. Using foil, place a layer of potatoes, a
layer of sliced onions, a layer of sliced mushrooms . Place a dab of
butter in three or four places. Salt and pepper to taste. Start all
over again. Do enough for your family. Cover with aluminum foil.
tuck in all seams and barbeque. This is so good.